Quadrupole moment measurements of TSD1 and TSD2 bands in 167 Lu (original) (raw)

Quadrupole moments of superdeformed bands in 193 Tl

The European Physical Journal A - Hadrons and Nuclei, 1999

Lifetimes of states in the two strongest superdeformed (SD) bands in 193 Tl were measured using the Doppler-shift attenuation method. The reaction 176 Yb(23 Na,6n) 193 Tl at a beam energy of 129 MeV was used and γ-rays were detected by the Gammasphere array. Quadrupole moments of 18.3(10) eb and 17.4(10) eb were extracted for SD bands 1 and 2, respectively, using the fractional Doppler-shifts of the SD transitions. The previously reported linking transitions of these SD bands to normal deformed near yrast levels could not be confirmed. No other candidates for linking transitions could be established.

Quadrupole moment of superdeformed bands in 151 Tb

European Physical Journal A, 1998

The quadrupole moments of the first two superdeformed (SD) bands in the nucleus 151Tb have been measured with the Doppler Shift Attenuation Method (DSAM) using the EUROGAM &#37-ray spectrometer. The first excited band (B2) is identical to the yrast SD band of 152Dy in terms of dynamical moments of inertia and &#37-ray energies. The measured relative quadrupole moments of the

Study of quadrupole moments of superdeformed bands in 145Gd

Nuclear Physics A, 2000

Superdeformed (SD) bands have been well established in many nuclei in the mass 150 region. It was shown that the observed behaviour of the dynamic moment of inertia J^ as a function of the rotational frequency has sensitive dependence on the number of occupied high-N intruder orbitals. The large dynamic moment of inertia of an SD band is indicative of an elongated shape, but since the dynamic moment of inertia is also sensitive to other phenomena (like pairing and alignment effects) the quadrupole moment of the SD band is a more reliable measure of the deformation. In this report we present mean lifetime measurements for SD bands in 145 Gd. In our previous experiment [1], three SD bands were found in this nucleus. The yrast SD band shows a smoothly decreasing dynamic moment of inertia with increasing rotational frequency. In the framework of the cranked Woods-Saxon-Strutinsky approach, we assigned a ix § 2 v7 l configuration to this band. The first excited SD band shows two subsequent band crossings at rotational frequencies of ~0.4 and 0.68 MeV, which were assigned to the subsequent alignments of an i 13 / 2 proton pair and a crossing of the i 13 / 2 [642]5/2 and in/ 2 [651]l/2 neutron orbitals, respectively. The vl\ orbital is not occupied. These features can be well reproduced by cranked Woods-Saxon-Strutinsky calculations, provided that the yrast SD band has a larger deformation than the first excited SD band. To check this interpretation, quadrupole moments have been measured for the SD bands in 145 Gd with the Doppler-shift attenuation method. High-spin states in 145 Gd have been populated in the u4 Cd( 36 S,5n) reaction at a beam energy of 182 MeV. The beam was provided by the LNL, Legnaro. The target consisted of a 1.2 mg/cm 2 114 Cd foil evaporated on a multi-layer backing. The recoiling 145 Gd nuclei were slowed down and stopped in Ta and Bi layers with a thickness of 1.2 mg/cm 2 and 55 mg/cm 2 , respectively. The 7-rays were detected using the GASP array. Its 40 Ge detectors are placed symmetrically in respect to beam direction in seven rings at angles of 35°, 60°, 72°, 90°, 108°, 120° and 145°. Spectra showing the Doppler shifted SD lines 17

Quadrupole Moments And Gamma Deformation Of Wobbling Excitations In 163Ln

AIP Conference Proceedings, 2005

Wobbling is an excitation mode unique to triaxial nuclei. Even though it is a general consequence of triaxiality in nuclei, it has so far only been observed in the odd-mass Lu isotopes around 163 Lu. The principal evidence for the wobbling mode is based on the pattern of rotational bands characterized and described by a wobbling phonon number and the decay between different bands belonging to the same family. A new measurement revealed lifetimes of states in an excited wobbling band for the first time and gave access to absolute transition probabilities for both in-band and interband transitions. A general recipe how to derive quadrupole moments for triaxial nuclei from experimental data is discussed. The results show a remarkable similarity of the quadrupole moments for the different bands, further supporting the wobbling scenario. A decrease of the quadrupole moments is observed with increasing spin. This is attributed to an increase in triaxiality with spin, which can at the same time explain the dependence of the interband transitions on spin. Such an increase in triaxiality is qualitatively reproduced by cranking calculations to which the experimental results are compared.

Low-lying bands with different quadrupole deformation in155Dy

EPJ Web of Conferences, 2014

To investigate the interplay between collective and single particle degrees of freedom in odd nuclei, Recoil distance Doppler-shift and Doppler-shift attenuation lifetime measurements were carried out for levels in 155 Dy in coincidence detection of gamma-rays. 26 lifetimes were determined using the Differential decay curve method. Particle plus triaxial rotor model (PTRM) calculations were performed to compare the experimental level scheme and transition strengths with theoretical ones in order to get information on the quadrupole deformation (ǫ,γ) of the bands. As a result, different quadrupole deformations for the one-quasineutron bands at low and medium spins are deduced.

Quadrupole deformed and octupole collective bands in 228Ra

Nuclear Physics A, 1998

Spins and parities for collective states in 228 Ra have been determined from conversion electron measurements with a mini-orange spectrometer. The fast-timing (t) method has been used to measure lifetimes of T 1=2 =550(20) ps and 181(3) ps for the 2 + 1 and 4 + 1 members of the K=0 + band, and T 1=2 7 p s a n d 6 ps for the 1 1 and 3 1 members of the K=0 band, respectively. The quadrupole moments, Q 0 , deduced from the B(E2; 2 + 1 !0 + 1 ) and B(E2; 4 + 1 !2 + 1 ) rates are in a good agreement with the previously measured value and the systematics of the region.

Low-lying bands with different quadrupole deformation in 133Nd

Physical Review C, 2000

The mean lifetimes of ten states in 133 Nd excited via the reaction 104 Pd( 32 S,2pn) at E 32 S ϭ135 MeV were measured by means of the recoil-distance Doppler-shift method. The spectra obtained by setting a gate on the shifted component of a transition directly feeding the level of interest were analyzed within the framework of the differential decay-curve method. The intraband transition strengths are compared to calculations within the particle plus rotor model which reveal differences in the quadrupole deformations ⑀ and ␥ of the bands studied.

Collective quadrupole dynamics and the band structure of the nucleus 127Cs

Nuclear Physics A, 1980

Excited states of '::Cs were populated in the "'ha, 4n) "'Cs reaction. Singles, prompt and delayed y-ray spectra, yy coincidence spectra, angular distributions and excitation functions were measured, and negative and positive parity bands established. The h, ,,2 families of excited levels in 127*12gCs and "'La were reproduced by core-particle coupling calculations, regardless of whether the cores were taken to be rigid triaxial rotors or to have all five quadrupole degrees of freedom. The hamiltonians for the latter case were based on microscopic calculations which attribute an important role to the y-dependence of the mass functions for collective quadrupole motion. From a core-quasiparticle analysis of the positive-parity levels in "'Cs, indications of a "Coriolis attenuation" anomaly were inferred.

Investigation of lifetimes in quadrupole bands of 142Gd

The European Physical Journal A, 2008

For a level scheme investigation of 142 Gd an experiment with the γ-spectrometer EUROBALL III has been carried out and lifetimes have been measured with EUROBALL IV using the Doppler-shift attenuation method. The high-spin states have been populated in these experiments by means of the 99 Ru( 48 Ti, 2p3n) reaction at a beam energy of 240 MeV and the 114 Sn( 32 S, 2p2n) reaction at 160 MeV, respectively. Reduced E2 transition probabilities B(E2) were determined for 15 members of four quadrupole bands. For the interpretation of the positive-parity even-spin quadrupole bands, calculations in the cranked Nilsson-Strutinsky as well as interacting boson models have been performed. From the former calculations it was concluded that the high-spin states of the (+, 0)1 band in 142 Gd represent a triaxial nucleus rotating around the longest principal axis.

Transition quadrupole moments at high spin in 133 Nd rotational bands

Lifetime measurements on the high-spin rotational bands in 133 Nd have been carried out by the Doppler-shift attenuation method using the GASP array. The 133 Nd nuclei were populated in the 104 Pd( 32 S,2pn) reaction at a bombarding energy of 135 MeV. The Doppler-broadened line shapes were analyzed for Au-backed and Gd-backed targets. Values of Q t ϭ4.7(5), 5.6͑5͒, and 7.4(4) e b have been determined for the mean transitional quadrupole moments of the ground-state band, the negative-parity band involving the neutron h 9/2 / f 7/2 intruder orbitals, and the band built on the neutron ͓660͔1/2 ϩ intruder orbital, respectively. The presently determined quadrupole moments are compared with those of the low-spin members of the bands derived elsewhere from recoil distance method measurements. The observed polarizing effects of the neutron intruder orbitals are compared with cranked shell model predictions.